The present invention relates to a light quantity adjusting device including an upper diaphragm blade and a lower diaphragm blade, which are provided so that they can reciprocate; a lens barrel; an image pickup device; and a method of controlling the image pickup device.
2. Description of the Related Art
Hitherto, an image pickup device, such as a digital still camera or a digital video camera, forms an object image by an image pickup lens. An image is formed by an image pickup element, such as a complementary metal oxide semiconductor (CMOS) image sensor or a charged coupled device (CCD) image sensor, disposed at the back side of the lens.
Here, if an object is bright, in order to reduce the quantity of light incident upon the image pickup element, the light quantity is restricted by moving a diaphragm blade provided at a light quantity adjusting device.
However, if the shape of a diaphragm opening formed by the diaphragm blade is a rectangular shape (such as a rhombic shape), an out-of-focus image of the formed image also has a rectangular shape, thereby making worse the out-of-focus image.
Accordingly, in a light quantity adjusting device including two diaphragm blades and a neutral density (ND) filter, there is provided a technology in which a third blade that moves together with the ND filter is provided. In addition, a polygonal diaphragm opening having five or more angles is achieved by two diaphragm blades and the third blade to improve an out-of-focus image.